How to download everything in that folder using boto3

Question

I want to download all the csv files that exist in s3 folder(2021-02-15). I tried the following, but it failed. How can I do it?

import boto3

s3 = boto3.resource('s3')
bucket = s3.Bucket('bucket')
key = 'product/myproject/2021-02-15/'
objs = list(bucket.objects.filter(Prefix=key))
for obj in objs:
    client = boto3.client('s3')
    client.download_file(bucket, obj, obj)

valueError: Filename must be a string

Answer 1

Marcin answer is correct but files with the same name in different paths would be overwritten. You can avoid that by replicating the folder structure of the S3 bucket locally.

import boto3
import os
from pathlib import Path

s3 = boto3.resource('s3')

bucket = s3.Bucket('bucket')

key = 'product/myproject/2021-02-15/'
objs = list(bucket.objects.filter(Prefix=key))

for obj in objs:
    # print(obj.key)

    # remove the file name from the object key
    obj_path = os.path.dirname(obj.key)

    # create nested directory structure
    Path(obj_path).mkdir(parents=True, exist_ok=True)

    # save file with full path locally
    bucket.download_file(obj.key, obj.key)

Answer 2

Since you are using resource, youu can use download_file:

import boto3

s3 = boto3.resource('s3')

bucket = s3.Bucket('bucket')

key = 'product/myproject/2021-02-15/'
objs = list(bucket.objects.filter(Prefix=key))

for obj in objs:
    #print(obj.key)
    out_name = obj.key.split('/')[-1]
    bucket.download_file(obj.key, out_name)  

Answer 3

Filter returns a collection object and not just name whereas the download_file() method is expecting the object name:

Try this:

objs = list(bucket.objects.filter(Prefix=key))
client = boto3.client('s3')
for obj in objs:
    client.download_file(bucket, obj.name, obj.name)

You could also use print(obj) to print the obj object in the loop to see what it actually has.

Answer 4

You could also use cloudpathlib which, for S3, wraps boto3. For your use case, it's pretty simple:

from cloudpathlib import CloudPath

cp = CloudPath("s3://bucket/product/myproject/2021-02-15/")
cp.download_to("local_folder")